This invention relates to thrust vector control systems and more particularly to vehicle control systems which utilize attachment surfaces to deflect flow for applying a control force to the vehicle.
In the past, flow exiting a nozzle has been deflected for thrust vector control purposes by a number of devices. For example, air or secondary fluid has been injected into the exhaust stream to deflect the entire stream. Also, nozzles have been mounted for movement to direct the thrust vector. In addition, exhaust streams have been directed over Coanda attachment surfaces such as jet flaps. Generally speaking, the above devices function to deflect the entire exhaust stream.
It is also possible to obtain thrust vector control by placing a movable vane or deflector in the exhaust stream, whereby only a portion of the exhust stream is deflected.
Although the above mentioned devices are fully capable of directing thrust vectors so as to produce the desired control forces, there are nevertheless certain disadvantages associated therewith. An obvious drawback related to the injection of fluid into the exhaust stream is that either ports must be provided in the nozzle or conduits are necessary to carry flow to the exit plane thereof. In specific applications, it may not be feasible to furnish such ports or conduits, due to weight, cost or structural factors. It should be evident that systems employing movable nozzles are both costly and structurally complicated.
In situations where deflection of an entire stream is not desirable, neither prior art Coanda surface, fluid injection, nor movable nozzle arrangements would be appropriate. Where a movable vane could furnish the required control force, drag, weight, cost and structural considerations could render it unsuitable for the selected application, particularly where hot exhaust gases are concerned.